Environment – Aluminium Hydroxide and Air Pollution Control

Ever wondered why factories still spew smoke even after all the tech upgrades? One simple, cheap material is stepping in to clean that mess: aluminium hydroxide. It’s not a fancy gadget, just a powder that loves grabbing nasty gases before they escape into the sky.

When you heat coal or oil, sulfur dioxide (SO₂) and other pollutants pop out. If you sprinkle aluminium hydroxide into the hot gas stream, it reacts fast, turning those gases into solid particles that can be filtered out. The chemistry is straightforward: Al(OH)₃ + SO₂ → Al₂(SO₄)₃ + H₂O. No need for complex catalysts or huge reactors.

How Aluminium Hydroxide Works

The magic starts with its high surface area. Tiny chunks of the powder give the gas plenty of spots to touch, so the reaction happens quickly. Because the reaction is exothermic, it actually releases a bit of heat, helping the process continue without extra energy input. The end product, aluminium sulfate, is water‑soluble, so you can wash it away and even reuse it in other industries.

In real plants, engineers feed the powder into a flue‑gas stream using a simple hopper. The particles stay suspended long enough to do their job, then a bag filter or electrostatic precipitator catches the solid waste. Maintenance is easy—just replace the powder when the hopper runs low.

Why It Beats Other Sorbents

Compared to limestone or lime, aluminium hydroxide works at lower temperatures and needs less space. Limestone needs to be heated to about 900 °C to break down, while Al(OH)₃ starts reacting around 200 °C. That means you save fuel and cut operating costs.

Another plus is selectivity. Some sorbents grab both sulfur and nitrogen oxides, which sounds good but can create unwanted by‑products. Aluminium hydroxide targets sulfur compounds mainly, keeping the downstream cleaning steps simpler.

Cost‑wise, the material is cheap enough for large‑scale use, especially when you factor in the lower energy demand. Plus, the by‑product can be sold to water‑treatment plants, turning waste into revenue.

So, if you’re looking at ways to shrink your plant’s carbon footprint, start with a bag of aluminium hydroxide. It’s a low‑tech, high‑impact solution that fits right into existing setups.

Bottom line: aluminium hydroxide isn’t a miracle cure, but it does a solid job at snatching sulfur out of the air without breaking the bank. For anyone serious about cleaner skies, it’s worth a closer look.